Jewel support for compasses



E. W. DAY.

JEWEL SUPPORT FOR COM'PASSES.

APPLICATION F ILED JULY 23,1917.

Patented Aug. 8, 1922.

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EDWIN W. DAY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPERRY GYROSCUPE COMFANY, F BROOKLYN, NEW YORK, A CORPORATIQN OF NEW YGRK.

JEWEL SUPPORT aeaeoa.

Application flied July 23,

' cation.

jewel supporting post. 25

form of compass of the typeknown as the This invention relates to magnetic compasses adapted for various, uses, such as for aeroplanes and infantry on the march. The objects of the invention are to render the construction of such compasses more durable to prevent breakage of the supporting jewel and the damaging of the point of the pivot pin.

Referring to the drawings in which what I now consider to be the preferred forms of my invention are shown:

Fig. 1 is a vertical section of: one form of compass with my invention applied thereto.

Fig. 2-is a detail thereof, showing the Fig. 3 is a vertlcal section of a modified marching or infantry compass.

Fig. 4 is a side elevation thereot.

Fig. 5 is a plan view on a reduced scale of the form of, compass shown in Fig. 1.

In the figures, 1 denotes any suitable form of casing for the compass. The said casing is shown as provided with a glass top 2 so that it is entirely enclosed. Within the easing is supported a post 3 within which is a yielding or resilient member such as a compression spring 4 adapted to support the usual jewel 6. Said jewel is shown as clamped between a member 7 with a flaring. mouth 41 and a recessed aperture at its base and a stem 8 on which said. member is threaded. By this construction a firm seat is provided for the jewel between the top of stem 8 and the shoulders of said recess and at the same time it is protected or cushioned from shocks by spring a. A remarkable reduction in the number of broken jewels has been efiected by the introduction of my invention. Post 3 and member 7 are preferably provided with means to prevent their relative rotation after assembling so that the jewel cannot work loose. Said means may consist of a strap 9 soldered or otherwise secured to post 3, and having a slot 10 provided therein. A pin 11 projecting from Specification of Letters Patent.

' portion.

FOR COMPASSES.

Patented Aug. 8, 1l22.

1917. Serial lilo. 132,126.

member 7 is confined within said slot so that no relative turning may take place. Said slot is preferably closed at the top as shown so that the pin and slot act also as a limiting means to prevent the jewel from rising above a predetermined height and also to hold the spring 4 under a slight compression.

On said jewel within the flaring mouth of member 7 rests the pivot pin 12 or the like by means of which the magnetic element or compass rose 13 is rotatably supported. The said rose is shown as built up of a plurality of interfitting members 14 and 15 between which are clamped the magnet or magnets 16. Around the periphery of the dome-shaped member 14: is clamped compass card proper 26 which is preferably of translucent material such as celluloid. The entire casing is preferably completely filled with a limpid liquid such as alcohol to relieve the pivot of the greater portion of the weight of the rose. to damp out quickly and effectively vibrations of the rose on spring 4. The reference indexor lubber line as shown in this instance is a bent wire or the like 17, secured atits base 18 to the casing and rising to a point near'the top of the casing where it is bent at 18 to form a horizontally-extending Adjacent a central portion of said wire an arrow 19 or other form of index is attached.

In Figs. 3 and 4: my invention is shown as applying to a somewhat different type of compass. According to this form the post 3 is supported from abar 23 extending across the interior of the casing 1 near the bottom. A flexible water tight diaphragm 24; is shown near the bottom of the casing. When the casing is being filled with liquid said dia phragm is pulled outwardly by means of a wrench adapted to engage threaded stem 25. When the casing is filled however the wrench is removed and the diaphragm allowed to exert a resilient pressure on the liquid so that any air bubbles may be gradually forced out of the casing. The comp-ass rose '14! in this instance is shown as supported from a jewel 6 by point 12, threaded in the height of the compass rose is regulated with respect to the glass top, so that the oint will be held within the flaring mouth oi the member 7 at all times no matter in a block 40, by which an adjustable pivot The liquid also serves what position the compass may be held, by reason of the proximity of the block 40 to the top 2 serving to prevent displacement; said jewel being supported from a spring 4 as before. The magnets 16 are shown as extending across the ring 27 to which the rose proper is secured. The periphery of the dome-shaped rose is provided with suitable markings 28 which are readable on the reference index 19' firmly secured to the casing adjacent the side Window 29. Said window is preferably provided with a lens 30 which serves at once to magnify the markings and to close the open ng, in the casing.

Having described my ,invention, what I claim and desire to secure by Letters Patent is:

. 1. In'a compass, thecombinat-ion with a casing having a top, of a magnetic rotatable element; a spring supported by said casing, a jeweled support on said spring on which said element is pivotally supported, guiding means between said support and casing, and means for maintaining said spring under compression with said magnetic element slightly below said top.

2. In a compass, the combination with a casing provided with a window at its side, of a magnetic rotatable element, a threaded member pointed at one end. and adjustably fixed in said element, a. spring supported by said casing, a jeweled holder provided with a flaring mouth on said spring, said element being pivotally supported on said holder, means for maintaining said spring under compression and means for regulating the proximity of the magnetic element to the top.

3. In a compass, the combination with a casing, of a spring supported by said casing,

a supporting element on said spring, a memher having ashouldered aperture on said element, a jewel clamped between the top of said element and the shoulders of said aperture, and a magnetic rotatable element pivotally supported on said jewel.

4. In a compass, the combination with a casing, of a spring supported by said casing, a supporting element on said spring, a member having an aperture and threaded to said element, a jewel between said element and member, means for preventing rotation of saidmembe'r with respect to said element, and a magnetic rotatable element pivotally supported on said jewel.

5. In a. compass, the'combination with a casing, of a magnetic rota-table element, a spring supported by said casing, a jeweled holder provided with a flaring mouth and mounted on said spring, said element being pivotally supported on said holder. and means for regulating the proximity of said element to the top of the casing.

6. In a compass, the combination with a casing, of a magnetic rotatable element, a spring supported by said casing, a threaded member pointed at one end and adjustably fixed in said element, a spring supported by said casing, and a jeweled holder provided with a flaring mouth and supported by said spring, said element being pivotally supported on said holder through said threaded member.

7. In a compass,'the combination with a casing, of a spring supported by said casing, a supporting element on said spring, a member having a shouldered aperture and detachably secured to said element, a jewel clamped between the top of said element and the shoulders of said aperture, and a magnetic rotatable element pivotally supportedon said jewel. I

In testimony whereof I haveafiixed my signature,

EDWIN W. DAY. 

